The present invention relates generally to storage and retrieval systems for magnetic cassettes or the like, and more particularly to an automatic exchanging system for magnetic tape cassettes which are alternatively transferred between a storage area and a play station. This invention may be embodied, for example, in a system for automatically exchanging a video tape cassette in a television (TV) broadcasting station, but it will be appreciated that it is also useful in other applications.
Known is a cassette automatic exchanging system having a robot arranged so as to select one from a large number of cassettes in a cassette storage case and to automatically supply it to an information recording/reproducing apparatus such as video tape recorder (VTR), such as disclosed in Japanese Utility Model Provisional Publication No. 61-61646, U.S. Pat. Nos. 3,831,197 and 3,938,190.
An important problem in the conventional automatic cassette exchanging systems relates to their cassette storage capacities being fixed respectively. This results in the fact that the automatic cassette exchanging system should be manufactured independently in accordance with the cassette storage capacity required in a TV broadcasting station and difficulty is encountered to easily expand the cassette storage area in response to requirements of addition of the cassette storage capacity. A further important problem in the conventional automatic cassette exchanging systems relates to the fact that the cassette exchanging operation is made by means of a single robot. This causes no cassette exchanging operation when the robot malfunctions and further causes slow cassette exchanging operation with the number of the stored cassettes being large. A still further aspect of the conventional automatic cassette exchanging systems is that the exchanging operation can be made only between cassettes equal in dimension to each other. This aspect would result in inconvenience in use of the system.